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Fill out the form and give us brief details.
We will get back to you with an indicative SIPs extension cost, so you know what to expect.
Once you have an idea of the price of a SIPs extension, you can then make an informed decision.

Or call the experts today on 0330 166 0877

Maximise Your Space with SIPs

Traditional cavity wall construction typically uses up to 350mm of wall thickness, which can eat into your usable floor space—especially in smaller extensions. In contrast, SIPs (Structural Insulated Panels) use just 147mm of thickness while still exceeding modern insulation and strength standards.

In a 4m x 5m extension, this difference alone can free up around 2m² of additional internal space—enough for extra storage, a larger dining area, or simply a more open feel. With SIPs, you’re not just building faster and stronger, you’re building smarter.

Space gained with SIPs

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Garden Rooms

Our extension kits are ideal for creating smart, warm and energy-efficient garden rooms

AltTextGarden Room Kitz

Our extension kits can be used to create an outdoor cabin or living space in your garden with high levels of insulation, ventilation and natural light, which make it cosy and comfortable all year round.

This high level of functionality gives the garden room owner limitless options for its use. Our research suggests that around 7 out of 10 people who have a garden room use it as a multipurpose space for relaxation, hobbies, or working from home.
sip cross section
sip cross section

New Garden Office?

A garden office from Extension Kitz offers the perfect blend of convenience, comfort, and productivity — right on your doorstep. Designed using our high-performance SIP panels and built in our UK factory, each structure is warm, energy-efficient, and fully customisable to suit your working needs. Whether you're after a quiet retreat for focused work or a stylish space to impress clients, your garden office is built faster, stronger, warmer and smarter.

With minimal disruption to your home and a sleek, modern design that complements any garden, Extension Kitz garden offices deliver long-lasting value. Pre-assembled off-site for a precision fit, they’re quick to install and fully compliant with Building Regulations — giving you peace of mind, improved work-life balance, and a beautiful workspace that adds value to your property.

Popular Finishes

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    Autumn Leaves Brick

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    Rustic Cream Brick

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    Midnight Render

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    Composite Cladding

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Different ways to use your garden room

Home Office
Subtitle Title or Description
Our kits are often used for garden offices and are a great way to accommodate home working, providing a dedicated space away from the noise and distractions of the family home. Crossing the garden to the home office is a commute to envy, and will certainly benefit the work-life balance.
Art studio or hobby room
Subtitle Title or Description
Garden rooms can make an ideal art studio or hobby room as they can be built with plenty of glazing to let in sunlight. Spending time surrounded by nature in a garden studio is relaxing, and the green space may fire up creativity.
Garden Gym
Subtitle Title or Description
Many customers use an extension kit to install a garden gym. Garden buildings are ideal for workouts as they offer privacy and a quiet space. Our extension kits are made to meet specific customer requirements, so they can fit as much gym equipment and storage as desired.

Your garden gym would also make a great location for a yoga studio or meditation space.
Guest Accommodation
Subtitle Title or Description
Your garden room would be useful extra accommodation for when guests come to visit or simply a space to entertain friends in comfort.
A Peaceful Haven
Subtitle Title or Description
A garden room extension kit could be used to create a relaxing summer house retreat or even a ‘man cave’ or ‘woman cave’ to provide a bit of tranquillity away from a busy household.

With all these benefits, it’s no surprise that 85% of homeowners who add a garden room report increased happiness and satisfaction with their home.

Designing the garden room

The design of your garden room will depend on how you want to use it. The versatility of our extension kits is in the fact that we can cut the panels to create an outdoor building of virtually any size.

Some clients have a firm idea of how they want their project to look and produce their own drawings, but others use an architect or work up their ideas with our in-house design team.

Fully Bespoke Sizing

"Build it faster, stronger, warmer and smarter"

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